Field of the Invention
The present invention relates to a technique for antenna configuration.
Description of the Related Art
Recently, wireless communication functions are mounted in various types of electronic devices. Many electronic devices are required to be downsized. Along with this requirement, antennas for wireless communication are required to be implemented in small spaces of these electronic devices. Under this circumstance, Japanese Patent Laid-Open No. 2012-085215 discloses an antenna structure having an antenna formed by using only a substrate and a conductive pattern without any member largely protruding from a plane of the substrate. In addition, Japanese Patent Laid-Open No. 2003-008325 discloses an antenna configured to have first and second antennas respectively arranged in occupation areas for the first and second antennas on the respective surfaces of an insulating substrate. According to Japanese Patent Laid-Open No. 2003-008325, the downsizing of an antenna apparatus including a plurality of antennas is achieved by making the occupation areas for the first and second antennas overlap each other at least partially when viewed from a direction at a right angle to the surface of the insulating substrate. Japanese Patent Laid-Open No. 2002-504770 discloses a compact planar diversity antenna including two radiation elements which are fixed to the two surfaces of a dielectric substrate and coupled without power feeding so as to cooperatively resonate in two adjacent frequency bands.
Along with mounting and the like of a MIMO communication function using a plurality of antennas, there are increasing demands for the downsizing of antennas. On the other hand, the downsizing of an antenna sometimes leads to a failure to ensure satisfactory antenna performance. That is, conventional antennas have difficulty in achieving a satisfactory reduction in antenna size while ensuring satisfactory antenna performance.
The present invention has been made in consideration of the above problems, and provides a technique of facilitating the downsizing of an antenna while ensuring antenna performance.